Element selecting device and elements comprising a plurality of optical filter units

ABSTRACT

In a filter conversion device employed in an optical system having a function for locating one of a plurality of color filter units in an optical path frame member is provided supporting a plurality of filter units and being arranged so as to be movable in a predetertmined plane between a light sending element and a light receiving element. A mechanism for controlling the frame member to move horizontally and vertically in the plane is also provided. Thus, the desired filter unit is located in the optical path without requiring a large space for movement.

BACKGROUND OF THE INVENTION

This invention relates to an element selecting device having a functioncapable of selecting one of a plurality of optical elements provided ona frame and locating the selected one in an optical path; and, moreparticularly, to an element selecting device arranged so as to besmoothly moved in a predetermined plane having a positional relationshipwith the optical path.

For example, as one example of the above-optical element, an opticalfilter is considered which is capable of passing light corresponding toa predetermined wavelength.

Conventionally, in electronic copy machines which make copies employingso-called electrophotographic system and in image processing devicessuch as an image scanners which scan a character side of an original andread the image data as electric signals, devices having a function forseparating the colors of original to make color copies and for obtainingsignals corresponding to a plurality of colors have been known.

Various color separation methods including a method in which thecharacter side of the original is irradiated by illuminating lightcorresponding to a specific wavelength have been generally considered.In many methods, one specific filter is selected from three types offilters, namely, red, green, and blue plus an ND filter which isincluded in most cases, and the selected filter is placed in an opticalpath from the character side of the original to a photoconductive drumor a light receiving element. The images corresponding to the originalwhich pass through various filters are scanned or transferred. In theelectronic copy machines, the passing light, having been passed throughthe various filters are developed, transferred, and fixed by utilizingcyan, magenta, and yellow toners so as to make color copies.

In the image processing device which places a selected filter from aplurality of filters in an optical path from the character side of theoriginal to the light receiving element, a disk plate on which aplurality of filters are provided around the same circumference of thedisk plate can be rotated about a shaft in parallel to the optical pathso that the desired position on the circumference where the filters areprovided matches the optical axis of the light being transmitted fromthe original to the light receiving element. By rotating the disk plate,the filters on the optical path are changed. Alternatively, a pluralityof specific filters are provided on a filter frame in series and bymatching the center of the filters with the optical axis, the filterframe can be moved in the direction where the filters are provided.Moreover, a plurality of filters are fixed around the rotating axis sothat the filters are placed in parallel to the rotating axis and theaxis is located in perpendicular to the optical axis. By turning thefilters around the rotating axis, one of them can be selected andselectively located on the optical path. In addition, the filters areoften larger circles than image circles on an optical path where theyare placed in any structure.

However, in these conventional structures as described above, due to aninstallation of the device including the filters and a motion of filterconversion mechanisms for placing the desired filter on the opticalpath, wide spaces are required, which prevent the entire device frombeing miniaturized.

In other words, for the device which utilizes a disk plate on which aplurality of filters are provided around the same circumference, a spacewhich is two times or more the diameter of the filters is required inthe vertical direction. On the other hand, for the device which movesthe filter frame where the filters are provided in a straight line, aspace which is equivalent to a motion stroke on both the left and rightsides in the moving direction of the filter frame (for example, thespace for three filters is required in case that the four filters areprovided) is required.

In other structures, wide installation and moving space are alsorequired.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an improvedelement selecting device which can locate the entire device in a smallspace without requiring a large space for the installation and motionthereof.

For this purpose, according to this invention, there is provided anelement selecting device for locating one of a plurality of elements ata desired position on a predetermined plane, said element selectingdevice comprises:

a plate-shaped member supporting said elements and being moveable insaid predetermined plane; and

control means for controlling said plate-shaped member so as to movehorizontally and vertically in said predetermined plane.

With the above constructed element selecting device, a frame supportinga plurality of optical elements, for example, optical filters, issmoothly moved and a desired element is located in an optical path of alight propagating from a light sending element to a light receivingelement.

DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 shows a longitudinal section schematic of an image scanningdevice embodying the filter conversion device according to the presentinvention;

FIG. 2 shows a schematic in the direction of an arrow II of FIG. 1,illustrating an arrangement of a filter conversion device according tothe invention;

FIG. 3 shows an explanatory view for explaining a moving state of thefilter conversion device of FIG. 2;

FIG. 4 shows an explanatory view for explaining a state in which thefilter conversion device of FIG. 2 is holizontally driven;

FIG. 5 shows an explanatory view for explaining a state in which thefilter conversion device of FIG. 2 is vertically driven;

FIG. 6 shows a hollow portion provided on a frame supporting the filterconversion device of FIG. 2, in which a pin provided on the filterconversion device is moved in response to a movement of the filterconversion device;

FIGS. 7(A) and 7(B) are explanatory views of a one embodiment of thepresent invention; and

FIGS. 8(A) and 8(B) are explanatory views of another embodiment of thepresent invention.

DESCRIPTION OF THE EMBODIMENTS

Referring to the attached drawings, embodiments of the present inventionwill be described below.

FIG. 1 shows a cross sectional view taken along a horizontal directionand viewed from the top of a scanning head 1 of an image scanning deviceincorporating the filter conversion device of the present invention.

Light from the character side of an original, not shown, is reflected bymirrors 2 and 3 and introduced to a lens 4. The lens 4 focuses the rayson the light reception surface of a CCD (Charge Coupled Device) sensor5. The CCD sensor 5 reads the image information as electric signals.

The CCD sensor 5 is a line sensor wherein picture elements arepositioned in a row. The CCD sensor 5 endlessly scans the character sideof the original in response to a movement of the scanning head 1 or theoriginal.

Between the mirror 3 and the lens 4, a filter frame 10 which is providedwith filters 11, 12, 13, and 14 is placed. As the filter frame 10 moves,a desired filter (11, 12, 13, or 14) is selectively placed in theoptical path of incident light to the lens 4. With the light having awavelength which passes through the desired filter, the original can bescanned.

As shown in FIG. 2 and FIG. 3, the filter frame 10 is provided with tworows of opening portions both in a horizontal direction and a verticaldirection wherein the filters 11, 12, 13, and 14 are respectivelymounted. The filter 12 is red; the filter 13 is green; the filter 14 isblue; and the filter 11 is an ND filter which is used for a monochromeoriginal or for a monochrome output even if a colour original isscanned.

The shape of the filters 11, 12, 13, and 14 is of a thin rectanglebecause the CCD sensor 5 is a line sensor which does not use the entireimage circle, but only a specific portion. Thus, the length of thefilter frame 10 along the vertical direction can be reduced, therebyreducing the entire space of the device.

The filter frame 10 is mechanically connected with a wall 1A as asupport member which is provided in the frame of the scanning head 1 bya link mechanism 20.

The link mechanism 20 consists of first link 21, a joint rod 22, andsecond links 23, the first and second links 21, 23 are connected withthe joint rod 22.

On the upper and lower sides of one end of the filter frame 10, one endof each first link 21 is pivoted so that one end of the first links 21can be freely slid. The length of the top first link 21 is the same asthat of the bottom first link 21.

The other end of each of the first links 21 is pivoted to both the endsof the joint rod 22 so that the first links 21 can be freely slid. Thepivot supporting point distance of the joint rod 22 is the same as thatof the first link 21 of the filter frame 10. Thus, a four-node parallellinkage is composed of the filter frame 10, first link 21, and joint rod22. At the pivot supporting point between the first links 21 and thejoint rod 22, one end of the second links 23 are pivoted so that it canbe freely slid. The other end of the second links 23 are pivoted to thewall 1A so that the second links 23 can be freely slid. The distancefrom the pivot supporting points to the wall 1A is the same as that thelength of the joint rod 22. In other words, a four-node parallel linkagecan be also formed with the wall 1A, second links 23, and joint rod 22.On the other hand, the upper and lower pivot supporting points of thesecond links 23 on the wall 1A are placed so that they are on a verticalline.

In the structure described above, the filter frame 10 is restrained byeach link of the link mechanism 20 so that the parallel state is alwaysmaintained and the position of the filter frame 10 can be varied in aplane along the vertical direction. The dimensions and position of eachelement (first links 21, joint rod 22, and second links 23) which formthe link mechanism 20 determine the movable range of the filter frame 10so that the center position of each of the four filters supported by thefilter frame 10 match the center optical axis of the light beingtransmitted from the mirror 3 to the lens 4. In addition, the plane ofthe lens 4, of the filter frame 10, of the mirror 3 and of the wall 1Aare aligned so that the filters can be slid into such alignment, as thefilter frame 10 moves along wall 1A.

In the following, a drive mechanism which places any filter that ispositioned by moving the filter frame 10 in the optical path will bedescribed.

A drive pin 15 is provided on the wall 1A side at the end where thefirst links 21 are pivoted on the filter frame 10. The drive pin 15protrudes to the opposite side of the wall 1A through an opening portion1B of the wall 1A, as shown in FIG. 6.

The drive pin 15 which is extruded to the opposite side of the wall 1Ais inserted into a slotted hole 30A on a guide plate 30 which isdescribed later so that the drive pin 15 can be slid along the slottedhole 30A. In addition, at the end where the drive pin 15 passes throughthe slotted hole 30A, one end of the drive arm 41 is pivoted as shown inFIG. 4.

The guide plate 30 is rectangular as shown in FIGS. 4 and 5. At thecenter thereof, a longitudinally slotted hole 30A is provided. At theupper and lower portions of one end thereof, one end of the links 31 arepivoted so that the links 31 can be rocked.

The distance of the pivot supporting point to the wall 1A is selected sothat the distance of the pivot supporting points is the same as that ofthe guide plate 30 and so that the vertical pivot supporting pointswhich pivot the links 31 are located on a vertical line. In other words,a four-node parallel linkage is composed of the guide plate 30, links31, and wall 1A. The guide plate 30 can be moved vertically along acircle the radius of which is equal to the length of the link 31 in themanner that the slotted hole 30A is kept horizontal.

The other end of the drive arm 41 is pivoted at a specific position onone side of a disk plate 51 which is fixed to a spindle of a horizontaldrive motor 50. In other words, when the horizontal drive motor 50rotates the disk plate 51, the drive arm 41 causes the drive pin 15 toreciprocate along the slotted hole 30A of the guide plate 30. As theresult, the filter frame 10 which is fixed to the drive pin 15 alsoreciprocates along the slotted hole 30A, namely, it moves horizontally.At both the ends of the reciprocation, the vertical line which passesthrough the center of the left side filters 12 and 13 and the right sidefilters 11 and 14 which are supported by the filter frame 10 matches thecenter of the optical path from the mirror 3 to the lens 4. In otherwords, the amount of reciprocation is equal to a pitch in the horizontaldirection of the right side filters 14 and 11 and the left side filters13 and 12. The horizontal drive motor 50 is a flange type pulse motor,and is fixed to a bracket plate 7 which is supported by the wall 1A withthe stud bolt 71.

A pin 30B is horizontally positioned at the center of the guide plate 30and below the slotted hole 30A. As shown in FIG. 5, the pin 30B isengaged to a link plate 32 so that one end of the link plate 32 can beslid and rotated. The other end of the link plate 32 is pivoted in aspecific position on one side of a disk plate 61 which is fixed to thespindle of a vertical drive motor 60. In other words, when the verticaldrive motor 60 rotates the disk plate 61, the guide plate 30 isvertically moved on a path which is regulated by the link 31. At bothends of the vertical motion, a horizontal line which passes through thecenter of the upper side filters 13 and 14 and the lower side filters 11and 12 which are supported by the filter frame 10 matches the center ofthe optical path from the mirror 3 to the lens 4. In other words, theamount of vertical motion is equal to a pitch in the vertical directionof the upper side filters 13 and 14 and lower side filters 11 and 12. Inaddition, the vertical drive motor 60 is a flange type pulse motor likethe horizontal drive motor and is fixed to the bracket plate 7 parallelto the horizontal drive motor 50.

Consequently, the filter conversion mechanism structured as above allowsthe horizontal drive motor 50 and the vertical drive motor 60 to movethe drive pin 15 on the route as shown in FIG. 6, thereby each filtersupported by the filter frame 10 is placed in the manner that the centerof each filter matches the optical path of the light being transmittedfrom the mirror 3 to the lens 4.

In other words, the filter frame 10 horizontally reciprocates one timewhenever the horizontal drive motor 50 rotates for one turn. Moreover,the filter frame 10 vertically reciprocates one time whenever thevertical drive motor 60 rotates for one turn. Consequently, when anyfilter, for example, the ND filter 11, is in the optical path, namely,when the center of the ND filter 11 matches the central optical axis, byrotating either the horizontal drive motor 50 or vertical drive motor60, another filter 12 or 14 located adjacent to the ND filter 11 can beplaced in the optical path (namely, the filter can be changed). Byrepeating such operations, the desired filter selected from the filters11, 12, 13, and 14 supported by the filter frame 10 can be placed in theoptical path.

Practically, reflection type photo-interrupters 81 and 82 are placed onthe bracket plate 7 where the horizontal drive motor 50 and the verticaldrive motor 60 are fixed in a manner that the reflection typephoto-interrupters 81 and 82 respectively face the disk plates 51 and61. In addition, when the ND filter 11 is placed in the optical path,the photo-interrupters 81 and 82 detect reflection members, not shown,fixed to the disk plates 51 and 61 so as to output signal correspondingto the detection of the ND filter 11. Since a positional relationshipbetween the ND filter 11 and each of the other filters have beendetermined in accordance with the position of the ND filter 11, thecharging of a filter placed in the optical path from the ND filter 11 toany other filter can be accomplished by sequentially controlling thehorizontal drive motor 50 and vertical drive motor 60 which are bothpulse motors.

For example, as shown in FIG. 2, by rotating the horizontal drive motor50 for a half turn, the ND filter 11 which is placed in the optical pathcan be converted to the red filter 12 as shown in FIG. 3. Moreover, byrotating the horizontal drive motor 50 for a half turn and by rotatingthe vertical drive motor 60 for a half turn, the ND filter 11 which isplaced in the optical path can be converted to the green filter 13 whichis positioned symmetrical to the ND filter 11 about the center of thefilter frame. Even if the filter which is placed in the optical path isuncertain, by rotating the horizontal drive motor 50 and the verticaldrive motor 60 until the photo-interrupters 81 and 82 generate a signalcorresponding to the detection of the ND filter 11, namely, until thereference filter (ND filter 11) is placed in the optical path, thefilter position can be initialized.

As another method for detecting the type of filter which is placed inthe optical path, where each filter placed in the optical path isprovided with a plurality of sensors and a plurality of detectionmembers mounted on the disk plates 51 and 61, different signals (or anycombination thereof) are output to completely detect the type of thefilter placed in the optical path.

The drive mechanism of the filter frame 10 can be constructed in anyother manner rather than being limited to the above embodiment. In theabove embodiment, independent motors, namely horizontal drive motor 50and vertical drive motor 60, are provided for the motions, namely,horizontal and vertical motions, for driving the filter frame 10.However, it is also possible to drive the filter frame 10 by a singlemotor. For example, as shown in FIG. 7(A) and (B), a small diameterepicyclic gear 200 is driven to rotate around a non-driven largediameter gear 100 by a single motor 55. Both of these gears are adaptedto be brought into engagement with each other. The motor is drivinglyconnected to driven gear 200 by any conventional motion transmissionmechanism, such as a pulley and endless belt mechanism mounted via alever or link system to enable the gear 200 to travel about gear 100 asshown in FIGS. 7a and 7b. A pin 210 is provided on one side of theepicyclic gear 200 so that it moves along a peri-trochoid curve definedby a gear ratio of the large diameter gear and the epicyclic gear 200.The position at which each of the filters 11, 12, 13, and 14 is placedin the optical path matches specific positions of the peri-trochoidcurve as shown in FIG. 7(B) by the dots along the dashed path of the pin210.

In a further embodiment, as shown in FIG. 8(A) and (B), gears 110 and120 are mounted on the shafts which are the center of rotation of thedisk plates 51 and 61 (FIGS. 4 and 5) through one-way clutches 115, 125which allows the force of reverse rotation to be transferred. The gears110; 120 are engaged with a drive gear 100 which is fixed to the spindleof the drive motor 55. Utilizing the structure illustrated in FIGS. 8aand 8b and as described above, depending upon the direction of rotationof the motor 55 (and of the gear 200), and by virtue of the one-wayclutches 115, 125, one of the disc plates 51, 61 (FIG. 8a) will bedriven to move the frame 10 either vertically or horizontally. Thus, bysequentially rotating the motor 55 in opposite directions, the filterframe 10 of FIG. 1 can be sequentially moved in the correspondinghorizontal and vertical directions via the slotted disc plates 51,61. Inthis embodiment of the drive mechanism, although the time required forfilter conversion is slightly longer than that of the above embodiments,the filter frame 10 of FIG. 1 can be driven via the disc plates 51, 61(FIGS. 4, 5) with only one motor, thereby reducing the cost of theproduction.

In addition, the above embodiments is applied to an image scanningdevice, it is also possible to apply it to a color copy machine.

Further, it may be considered that a plurality of Fresnel lenses areprovided on the frame instead of the filters as the optical elements,with each of the lenses respectively having a predetermined focallength. This arrangement is able to be applied to a copy machine havinga function being capable of varying a magnifying power, and the like.

What is claimed is:
 1. An element selecting device for locating one of aplurality of elements at a desired position on a predetermined plane,said element selecting device comprising:a plate-shaped membersupporting said elements and being movable in said predetermined plane,said plate-shaped member supported by a plurality of link members, eachof said link members being arranged in parallel with each other; andcontrol means for controlling said plate-shaped member so as to movehorizontally and vertically in said predetermined plane; said elementscomprising a plurality of optical filter units, each of said filterunits respectively passing a light corresponding to a predeterminedwavelength, and wherein said predetermined plane is placed between alight sending element and a light receiving element and perpendicular toa central optical axis of light propagating from said light sendingelement to said light receiving element.
 2. The element selecting deviceaccording to claim 1 wherein said control means comprises a drive sourcefor generating a drive force and transmitting means mechanicallyconnected to said plate-shaped member for transmitting said drive forcefrom said drive source to said plate-shaped member.
 3. The elementselecting device according to claim 2 wherein said drive sourcecomprises two motors having drive spindles which are respectivelyconnected to circle-shaped plates, said plate-shaped member beinghorizontally and vertically movable in said predetermined plane inresponse to rotation of each of said circle-shaped plates.
 4. Theelement selecting device according to claim 3 wherein said transmittingmeans comprises a guide plate member provided on said plate-shapedmember including a projection part connected to one of said circleshaped plates through a link member movable in one of the horizontal andvertical directions in response to rotation of said one of saidcircle-shaped plates, said projection part having an opening extendingalong the other direction in which a pin member fixed on said framemember and connected to the other of said circle-shaped plates throughan arm member is slidably moved.
 5. The element selecting deviceaccording to claim 2 wherein said drive source comprises a single motorhaving a spindle which is connected to a gear member, and wherein saidtransmitting means comprises a guide plate member provided on saidplate-shaped member including a projection part connected to acircle-shaped plate adapted to be brought into engagement with said gearmember through a link member movable in one of horizontal and verticaldirections in response to rotation of said circle-shaped plate, and saidguide plate having an opening extending along the other of saiddirections in which a pin member fixed on said plate-shaped member andconnected to another circle-shaped plate adapted to be brought intoengagement with said gear member through an arm member is slidablymoved, each of said circle-shaped plates, respectively, being connectedto one-way clutch members and being respectively rotatable in responseto only one rotating direction of said gear member.
 6. The elementselecting device according to claim 1, wherein said control meansfurther controls said plate-shaped member such that one of said elementsis located at said desired position in accordance with a positionalrelationship between said one of said elements and a predeterminedelement supported on said plate-shaped member.
 7. A filter conversiondevice for placing one of a plurality of filter units between a lightsending element and a light receiving element, each of said filter unitsrespectively passing a light corresponding to a predeterminedwavelength, said filter conversion device comprises:a frame membersupporting said filter units and being movable in a predetermined planeperpendicular to a central optical axis of a light propagating from saidlight sending element to said light receiving element; two motor membersof which spindles are respectively connected to circle-shape plates,said frame member moving in said predetermined plane horizontally andvertically in response to a rotation of each of said circle-shapeplates; and a guide plate member provided on said frame member includinga projection part connected to one of said circle shape plates through alink member movable in one of horizontal and vertical directions inresponse to a rotation of said circle shape plate, and having a hollowportion along the other of direction in which a pin member fixed on saidframe member and connected to the other of said circle-shape platethrough an arm member is glidingly moved.
 8. The filter conversiondevice according to claim 7 wherein said filter units comprises a redfilter, a green filter, and an ND filter.